Westinghouse SK-32H240S Continued problems

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

Where'd you buy your transformers? Did you see my post above? I've replaced a few swollen caps on these but the problem has always been usually 1 but sometimes 2 bad transformers.

[bpopilek]

Re: Westinghouse SK-32H240S Continued problems

Okay! I finally got it working! I have two defective power supplies here, and both had a single fried back light inverter. I have a brand new replacement that I ordered off of ebay, and apparently that was my problem. I tested the ohms on each inverter, and found that the new one had a much higher resistance than the originals. So I replaced that one with one of the other original stock inverters, and viola it worked! So my only other question at this point is this. Do all three back light inverters need to be within a certain percentage of each other, or do they all need to be equivalent to what came in it stock. The original inverters had a ohm rating of 1730, and the replacement I received was around 1850. I would like to buy the necessary parts to revive my other board so I can either keep it as a spare or sell it. So if I bought 2 more from the seller that I got this first one from and they are all 1850 ohms, would it work? Thanks!

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

The one you ordered was probably bad. Did yours come from China?

[bpopilek]

Re: Westinghouse SK-32H240S Continued problems

no I ordered it from a US supplier.

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

I returned the 10 transformers I ordered from China, and have 15 more here from shopjimmy that I havent installed yet. Jimmy gets these from Darfon so I will report back when I put these in..

I had the same issue where it wouldn't work with the chinese transformer, but when I took a working OEM transformer from another power board it worked fine.

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

Finished with all these. Out of 18 tvs I purchased...

(1) cracked screen

(2) with a single vertical line down the screen which was bad panel and could not be fixed with tab bonds.

(15) with at least one bad backlight transformer on PS board (one board had 2 bad ones). All shopjimmy replacement transformers worked. Also a few misc. bloated caps usually the same 2 or 3 noted above.

[hezandry]

Re: Westinghouse SK-32H240S Continued problems

This appears to be and should be troubleshot as 'two seconds to black'. The pictures aren't very good, and without a picture of the bottom of the power supply / inverter it's going to require a little extra work. Since you will be doing the work, I don't mind.

The following tests should be done in as dark a room as possible - you are going to be looking for a brief flash from the backlights.

Set everything up so you can see the back of the LCD panel. There are usually enough light leaks that you can see if the backlights are on even from the back.

Disconnect all of the cables to the backlights except one. Turn on the TV. You should see a brief flash before the protection circuits kick in. Turn the TV off, unplug the first CCFL and plug in the next. Turn on the TV and watch for the flash. Repeat for each of the remaining 4 CCFLs.

With luck, all of the CCFLs except one will light. If none light, repeat, but hooking up a pair at a time, rather than only one.

Report your results.

PlainBill

New to me tv. PlainBill, I read all of the posts in this thread and others but have not found a follow up to the individual light test. If one bulb is not lighting will this cause these symptoms? Upon power up, logo comes on for 3 seconds or so, then black then the input starts. Lasts about ten seconds then black.
Cannot see any image using a flashlight, second bulb from the top does not light.
I cannot see any bad caps or burns at any transformers.

[kevinm34232]

Re: Westinghouse SK-32H240S Continued problems

When everything is working, the backlight will still go out without an input connected, when you hit a button on remote it should light up again.

[jesselyons2002]

Re: Westinghouse SK-32H240S Continued problems

I just got one of this. The guy replace two of the transformer on it and it still dies out. I took out all three transformer. Test both primary and secondary wiring. All came into spec.

Then took out all the caps out. All tested good and within spec. Check all diode. All came out good and voltage was right. Only thing I haven't test was the transitor or I think there call mosfet. <--Correct me if im wrong.

Oh another I test was the ccfl test. By taking one out and see if it flash. All of them did.

One more test. Check the voltage at ccfl with everything plugged in. Was getting 400+ volts from each one when the tv screen was on and then 4.8 volts from each ccfl when the tv screen went off.

Please someone help me. I believe in all of you that help.

[martino]

Re: Westinghouse SK-32H240S Continued problems

parting out a westinghouse sk-32h240 with a cracked screen...
inbox me if you need parts...

[tvdoc757]

Re: Westinghouse SK-32H240S Continued problems

hi all have any of you guys found any new developments on the 2 seconds to black condition i 2 have recaped the board and replaced the transformer that was burnt tested all the ccfls looking for any thing else to test or try to get her up and running thanks in advance

[tvdoc757]

Re: Westinghouse SK-32H240S Continued problems

hello all i am trying to get a new psu/inverter board for my WESTINGHOUSE SK-32H240S the board number is 4H.B0700.051/B1 / B070-401 i know that thare is 2 difrent boards for this tv my question is are thay interchangeable i have attached a pic of the board i have now i appreciate any in put thank you all in advance. the number on the barcode is 5604264011g74900274bp1b

[budm]

Re: Westinghouse SK-32H240S Continued problems

You need to match the number on the barcode sticker, that is the part number of the PCBA (Printed Circuit Board Assembly), the other numbers as printed directly on the board is the P/N of the blank board before it is stuffed with components, they can use the same blank board for making many PCBA. So what are the numbers as printed on the barcode?

[martino]

Re: Westinghouse SK-32H240S Continued problems

Hello gentleman,
we are trying to figure out if the PSU board that I have will work in his TV.
Plugin's etc seem to be the same,but board component etc different,eventhough it's the same make model TV !!
I took pics of the board and barcode and legend for the 22pin plug...

[tvdoc757]

Re: Westinghouse SK-32H240S Continued problems

the number on the barcode is 5604264011g74900274bp1b thank you for your help.

[budm]

Re: Westinghouse SK-32H240S Continued problems

http://www.shopjimmy.com/catalogsear...use+sk-32h240s, he has a sub for the your board.
http://www.shopjimmy.com/westinghous...t-inverter.htm

http://www.shopjimmy.com/westinghous...t-inverter.htm

You should contact SJ for verification.

[Fancychancie]

Re: Westinghouse SK-32H240S Continued problems

Going from here will be more difficult since most of the easy things are already tested.
Basically the inverter PWM IC works as "all or nothing". Either all the ccfls and its circuitry works or nothing. The PWM IC will take 2 to 3 seconds to make that decision.
The main culprits are bad caps, bad ccfls, bad ccfl wiring and bad inverter transformer windings. From your tests, it seems the only left is the pwm IC and it circuitry which isn't easy.

couldn't i some how override that decission to shut off the backlights and jump power somewhere to force the backlights on? or provide my own power from another source to turn on the existing transformers?

I'm not the type of person to "over ride" any protection mechanism. For one, I don't want to be liable for any ramifications of such actions.
Others have done it using either/or
a) resistor
b) capacitor
c) shorting out pwm ic pins

Application:
Westinghouse SK-32H240S (same board as MajesticMike, see pics from post #37)
Issue:
TV turns on, see Westinghouse logo (1 sec), screen goes black, picture shows as well as audio (1-2 sec), screen goes black audio still present.
Testing (summarized):
I've put flashlight to screen during blackout condition, I do not see any picture (I don't know if my flashlights are bright enough). I've desoldered all caps and transformers from the PCB and externally tested them with multimeter (Fluke 87V - sorry don't have an ESR meter). Replaced 3 bad caps and 1 (melted) transformer. I've verified the ceramic caps (blue ones) have "OL" when testing between their legs. I've tested all diodes and resistors. I've verified all 6 CCFLs work (by plugging in 1 at a time then turning TV on). In the main connector at top of power supply board I've verified 5v is present on BL_ON, PWR_ON, 5VS pins and 12v is present on the applicable audio pins, all are within specification based on the printed key next to the connector.

I believe I'm at the point where retiredcaps & MajesticMike left off in post #41.
Any other ideas? Did you ever get it working MajesticMike?

Thanks, Chance.

[TV1964]

Re: Westinghouse SK-32H240S Continued problems

This appears to be and should be troubleshot as 'two seconds to black'. The pictures aren't very good, and without a picture of the bottom of the power supply / inverter it's going to require a little extra work. Since you will be doing the work, I don't mind.

The following tests should be done in as dark a room as possible - you are going to be looking for a brief flash from the backlights.

Set everything up so you can see the back of the LCD panel. There are usually enough light leaks that you can see if the backlights are on even from the back.

Disconnect all of the cables to the backlights except one. Turn on the TV. You should see a brief flash before the protection circuits kick in. Turn the TV off, unplug the first CCFL and plug in the next. Turn on the TV and watch for the flash. Repeat for each of the remaining 4 CCFLs.

With luck, all of the CCFLs except one will light. If none light, repeat, but hooking up a pair at a time, rather than only one.

Report your results.

PlainBill

I replace the power supply inverter board and the tv cuts off after a few seconds, but I can heard the sound. I performed the test you mentioned and one of the CCFL is not working. How do I fix this ?

[TV1964]

Re: Westinghouse SK-32H240S Continued problems

I replace the power supply inverter board and the tv cuts off after a few seconds, but I can heard the sound. I performed the test you mentioned and one of the CCFL is not working. How do I fix this ?

[johnboy1313]

Re: Westinghouse SK-32H240S Continued problems

You'll have to open the panel and replace the bulb if you can find one.